Device and method for measuring axial acceleration sensitivity of circular tube hydrophone

Abstract

The invention relates to a device and a method for measuring the axial acceleration sensitivity of a circular tube hydrophone. The device comprises a base, a hasm, an end cover, a circular tube hydrophone to be measured, a top cover, a pre-amplifier, an accelerometer and a vibration exciter, wherein the base comprises a base plate and a semicircular pipe arranged in the center of the base plate in a protruding mode, and a plurality of installation holes of different sizes are formed in the base plate so that vibration exciters of different connectors can be installed in a matched mode; a lead groove is formed in the top of the semicircular pipe; the Hu is of a semicircular pipe structure, the pipe diameter of the Hu is matched with the semicircular pipe in the center of the base plate, and a plurality of threaded holes are formed in the middle of the inner wall of the Hu at intervals in the height direction. Through reasonable structural design, the primary hydrophone and the pre-amplification circuit are integrally designed, the axial acceleration response of the circular tube hydrophone can be compared and represented, and an important basis is provided for performance evaluation and application of the circular tube hydrophone.

Description

Technical field:

[0001] The invention belongs to the technical field of hydrophone detection, and relates to a device and a method for measuring the axial acceleration sensitivity of a circular tube hydrophone. Background technology:

[0002] The circular tube hydrophone is an ideal choice for towed array systems due to its high sensitivity and wide-band response characteristics. However, it will be disturbed by axial and radial vibration signals during the acoustic detection process. Therefore, acceleration sensitivity is one of the important performance indicators of the circular tube hydrophone, which can reflect the response characteristics of the hydrophone when subjected to acceleration. Therefore, measuring the acceleration sensitivity of the hydrophone is crucial to evaluating its performance in water.

[0003] At present, when testing circular tube hydrophones of different sizes, it is necessary to replace multiple sets of fixtures, which is complicated to operate. In addition, the preamplifier circuit of the hydrophone is generally placed on the outside during the test, and the electromagnetic shielding effect is relatively poor. At the same time, the existing test methods are often only applicable to circular tube hydrophones of a single size, and the efficiency of replacing different fixtures when performing comparative tests on hydrophone performance is low, and the consistency is poor. Summary of the invention:

[0004] The technical problem to be solved by the present invention is to provide a device and method for measuring the axial acceleration sensitivity of a circular tube hydrophone. Through reasonable structural design and structural integration design of a first-stage hydrophone and a preamplifier circuit, the axial acceleration response of the circular tube hydrophone can be compared and characterized, providing an important basis for the performance evaluation and application of the circular tube hydrophone.

[0005] The technical solution of the present invention is to provide a circular tube hydrophone axial acceleration sensitivity measurement device, comprising a base, a Hafu, an end cover, a circular tube hydrophone to be measured, a top cover, a preamplifier, an accelerometer and an exciter; wherein,

[0006] The base includes a chassis and a semicircular tube protruding from the center of the chassis. The chassis is provided with a plurality of mounting holes of different sizes to match the installation of vibrators with different interfaces. A lead groove is provided on the top of the semicircular tube.

[0007] The Hafu is a semi-circular tube structure and its diameter matches the semi-circular tube in the center of the chassis. A plurality of threaded holes are arranged at intervals in the height direction in the middle of the inner wall of the Hafu.

[0008] The diameter of the end cover matches the outer diameter of the semicircular tube, and the end cover is mounted on the top of the semicircular tube by fasteners;

[0009] The circular tube hydrophone to be tested is integrally cast and fixed inside the circular tube formed by the semicircular tube and the Hafu.

[0010] The top cover is a cylinder with an outer diameter smaller than the inner diameter of the Hafu. There are two top covers, which are respectively installed at the upper and lower ends of the circular tube hydrophone to be tested. One end of the top cover facing the circular tube hydrophone to be tested is provided with a countersunk hole with the same size as the outer diameter of the circular tube hydrophone to be tested. The end of the circular tube hydrophone to be tested is located in the countersunk hole and has an interference fit with the top cover. A lead hole is also provided on the top of the top cover at the upper end. The lead of the circular tube hydrophone to be tested passes through the lead hole and is connected to the input end of the preamplifier.

[0011] The preamplifier is packaged in a metal shell on the outside and contains a preamplifier circuit inside. The preamplifier is placed above the hydrophone to be tested and fixed inside the circular tube formed by the semicircular tube and the Hafu tube, and the wires leading out from the output end of the preamplifier are clamped by the end cap.

[0012] The exciter is installed on the corresponding chassis mounting hole;

[0013] The accelerometer is connected to the vibrator to ensure that the circular tube hydrophone to be tested and the accelerometer maintain the same amplitude during vibration;

[0014] The base and the Hafu are both made of metal.

[0015] The present invention is based on the accelerometer method test and can adapt to circular tube hydrophones of different sizes through reasonable structural design. The preamplifier is placed in the metal cavity to ensure that the acceleration response signal output process is inside the shielding layer. The structure is simple and the test is stable, which can effectively avoid the design defects existing in the existing scheme.

[0016] Preferably, the semicircular tube and the Hafu are enclosed into a circular tube and then fastened by screws.

[0017] Preferably, a protrusion with an inner diameter of 11.8 mm and an angle of 120° extends from the middle of the inner wall of the semicircular tube to prevent the inner circular tube hydrophone to be tested from directly contacting and fitting with the inner wall.

[0018] Preferably, the installation position is selected according to the length of the cylindrical hydrophone to be tested, and long screws are used to pass through the corresponding screw holes on the side wall of the Hafu to tighten the top cover, so that a gap is set between the Hafu as a whole and the cylindrical hydrophone to be tested, and the remaining screw holes without long screws are closed with screws.

[0019] Preferably, the base, Hafu, end cover and top cover are made of aluminum alloy.

[0020] Preferably, the preamplifier circuit operates in a frequency band of 10 Hz to 10 kHz, outputs in a differential form, and has an amplification of 40 dB.

[0021] Preferably, the sensitivity of the accelerometer 7 is 100 mv / g.

[0022] Preferably, when the accelerometer is in use, one side is connected to an accelerometer power supply, and the analog signal is connected to an oscilloscope.

[0023] The present invention also provides a measuring method for the axial acceleration sensitivity measuring device of the circular tube hydrophone as described above, wherein the accelerometer and the chassis of the measuring device are fixed on the table surface of a rigid vibration table, and the axial vibration acceleration borne by the circular tube hydrophone to be measured is measured by the accelerometer; the circular tube hydrophone to be measured and the accelerometer are powered by a low-voltage power supply and an accelerometer power supply respectively, the vibration table maintains vertical vibration, a sinusoidal signal of a specific frequency is emitted by a signal source and amplified by a power amplifier and then transmitted to the vibration table; the circular tube hydrophone to be measured then converts the acquired sound pressure information into an electrical signal, and inputs it into a preamplifier and a filter for further processing, and the processed voltage peak-to-peak value U of the circular tube hydrophone to be measured and the accelerometer is converted into an electrical signal; H with U a The open-circuit voltage at the output end is displayed on the oscilloscope. Finally, according to formula (1), the axial acceleration sensitivity M of the circular tube hydrophone to be tested can be obtained: a :

[0024]

[0025] Where M ar is the sensitivity of a standard accelerometer.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The present invention proposes a method for measuring the axial acceleration sensitivity of a circular tube hydrophone. The present invention adopts an accelerometer method to measure the acceleration sensitivity. Under the premise of simulating the acceleration environment, the hydrophone to be tested and the preamplifier circuit are placed in the same electromagnetic shielding environment. The circular tube hydrophone to be tested is hard-connected to the test table to ensure that there is no unnecessary signal interference and vibration loss. The device can be adapted to circular tube hydrophones of different sizes. The test process is fast, accurate and has good stability. Description of the drawings:

[0028] Figure 1 It is a schematic diagram of the local structure of the present invention;

[0029] Figure 2 It is a schematic diagram of the device of the present invention when in use;

[0030] Figure 3 This is a measurement principle diagram of the present invention. Specific implementation method:

[0031] The present invention will be further described below with reference to the accompanying drawings:

[0032] The structural part of the axial acceleration sensitivity measuring device of the present invention mainly includes a base 1, a Hafu 2, an end cover 3, a circular tube hydrophone to be measured 4, a top cover 5, a preamplifier 6, an accelerometer 7, and an exciter 8.

[0033] like Figure 1 , 2 In this embodiment, the base 1 is made of aluminum alloy. The base includes a bottom chassis, which is a cylinder with a diameter of φ64mm and a thickness of 10mm. The surface diameters of φ40mm and φ50mm are respectively provided with φ4.5mm and φ9.5mm circular mounting holes to match the installation of exciters 8 with different interfaces. The center of the disk is raised to a height of 120mm, and the outer diameter is φ28mm and the inner diameter is φ14mm. A lead groove is opened on the top of the semicircular tube, and two M4 threaded holes are opened on both sides. The wires led out from the output end of the preamplifier 6 are clamped by the end cover 3. The inner diameter of the semicircular tube extends from the middle of the inner wall of the semicircular tube to φ11.8mm, and the angle is 120°. The hydrophone 4 to be tested and the preamplifier 6 are arranged up and down and placed on the inner side of the semicircular tube of the base 1, and then the semicircular tube and the Hafu 2 are fixed by the screws on the Hafu 2. Six M4 threaded holes are opened on the side of the semicircular tube, and they are tightened with the Hafu 2 by screws during installation. When installed and used, the axial direction of the circular tube hydrophone 4 to be tested is consistent with the vibration direction of the exciter 8 .

[0034] In this embodiment, Hafu 2 is made of aluminum alloy. The overall structure is semi-circular tube, with an outer diameter of φ28mm, an inner diameter of φ14mm, and a height of 85mm, so that it can be combined with the semi-circular tube to form a circular tube. There are 12 M3 threaded holes in the middle of the inner wall of Hafu 2. The installation position is selected according to the length of the hydrophone. The top cover 5 is tightened with M3 long screws. Hafu 2 as a whole does not contact the hydrophone to be tested. The remaining holes are sealed with M3 short screws when not in use. There are six φ4.5mm through holes on the side to tighten with the base 1.

[0035] In this embodiment, the end cap 3 is made of aluminum alloy. The end cap has a diameter of φ28 mm and a height of 4 mm. Two through holes with a diameter of φ4.5 mm are opened on the surface to clamp the signal line of the hydrophone 4 to be tested through screws and the base 1.

[0036] In this embodiment, the circular tube hydrophone 4 to be tested is integrally cast. When in use, it is hard-connected to the cavity formed by the semicircular tube and the Hafu 2. The base 1 and the Hafu 2 are both made of metal materials, so the interior forms a shielded environment to avoid the introduction of external interference. There are two pins on the upper end surface of the component, namely the positive and negative poles of the circular tube hydrophone signal to be tested, which are connected to the input end of the preamplifier 6.

[0037] In this embodiment, the top cover 5 is made of aluminum alloy. The whole is a cylinder with an outer diameter of φ11.8 mm. There are two top covers 5, which are respectively installed at the upper and lower ends of the circular tube hydrophone 4 to be tested. The end of the top cover 5 facing the circular tube hydrophone 4 to be tested is inwardly concave with a countersunk hole of the same size as the outer diameter of the circular tube hydrophone 4 to be tested. The end of the circular tube hydrophone 4 to be tested is located in the countersunk hole and has an interference fit with the top cover 5. The fixed position is at both ends of the hydrophone to avoid the sensing part of the circular tube hydrophone 4 to be tested, and the lead hole is left to connect the preamplifier 6. The inner diameter of the countersunk hole can be adapted according to the size of different circular tube hydrophones.

[0038] In this embodiment, the preamplifier 6 is encapsulated in a metal shell, and the preamplifier circuit is inside, and the preamplifier circuit is connected through pins. The preamplifier circuit has an operating frequency range of 10Hz to 10kHz, outputs in a differential form, and has an amplification of 40dB.

[0039] In this embodiment, the sensitivity of the accelerometer 7 is 100mv / g. The accelerometer 7 is hard-connected to the exciter 8 to ensure that the circular tube hydrophone 4 to be tested and the accelerometer 7 maintain the same amplitude during vibration. When in use, one side is connected to the accelerometer power supply, and the analog signal is connected to the oscilloscope.

[0040] The measurement principle diagram used in the present invention is as follows Figure 3 The measurement system includes a signal source, a power amplifier, a component to be measured, an accelerometer, an exciter, a filter, an oscilloscope, an accelerometer power supply, a low-voltage power supply for a hydrophone, etc. The accelerometer and the circular tube hydrophone to be measured are fixed together on the table of a rigid vibration table (exciter), and the accelerometer is used to measure the axial vibration acceleration borne by the circular tube hydrophone to be measured. During the measurement, the circular tube hydrophone to be measured and the accelerometer to be measured are powered by the low-voltage power supply and the accelerometer power supply respectively. The vibration table maintains vertical vibration, and a sinusoidal signal of a specific frequency is emitted by the signal source and amplified by the power amplifier before being transmitted to the vibration table. The circular tube hydrophone to be measured then converts the acquired sound pressure information into an electrical signal, and inputs it into the preamplifier and the filter for further processing. Finally, the peak-to-peak value U of the processed voltage of the circular tube hydrophone to be measured and the accelerometer is converted into an electrical signal. H with U a The open-circuit voltage at the output is displayed on the oscilloscope. Finally, according to formula (1), the axial acceleration sensitivity M of the circular tube hydrophone to be tested can be obtained: a :

[0041]

[0042] Where M ar is the sensitivity of a standard accelerometer.

[0043] The above test scheme can also use the laser vibrometer method, that is, the laser beam output by the laser probe is focused on a certain surface in the vibration direction of the hydrophone, and the reflected laser returns to the laser probe. The laser vibrometer decoder directly measures the vibration acceleration of the hydrophone. Then, according to the open circuit voltage U output by the hydrophone H , we can get the acceleration sensitivity M of the circular tube hydrophone to be tested a .

[0044] The mounting structure of the present invention is adapted to circular tube hydrophones of different sizes by adding a fixed top cover, and the metal end cover is hard-connected to the hydrophone and the vibration platform to ensure loss-free vibration transmission. The preamplifier circuit is also placed in an electromagnetic shielding environment to avoid introducing unnecessary interference. In this way, the axial acceleration response capability of the circular tube hydrophone at different frequencies can be accurately compared, and the test results provide data reference for the performance evaluation of the hydrophone.

[0045] The above is only an explanation of the preferred embodiments of the present invention, which should not be construed as a limitation on the claims. Any equivalent process changes made using the present invention specification are included in the patent protection scope of the present invention.

Claims

1. A device for measuring the axial acceleration sensitivity of a circular tube hydrophone, characterized in that: It includes a base, Hafu, end cover, a circular tube hydrophone to be tested, a top cover, a preamplifier, an accelerometer and an exciter; among which, The base includes a chassis and a semicircular tube protruding from the center of the chassis. The chassis is provided with a plurality of mounting holes of different sizes to match the installation of vibrators with different interfaces. A lead groove is provided on the top of the semicircular tube. The Hafu is a semi-circular tube structure and its diameter matches the semi-circular tube in the center of the chassis. A plurality of threaded holes are arranged at intervals in the height direction in the middle of the inner wall of the Hafu. The diameter of the end cover matches the outer diameter of the semicircular tube, and the end cover is mounted on the top of the semicircular tube by fasteners; The circular tube hydrophone to be tested is integrally cast and fixed inside the circular tube formed by the semicircular tube and the Hafu. The top cover is a cylinder with an outer diameter smaller than the inner diameter of the Hafu. There are two top covers, which are respectively installed at the upper and lower ends of the circular tube hydrophone to be tested. One end of the top cover facing the circular tube hydrophone to be tested is inwardly concave with a countersunk hole of the same size as the outer diameter of the circular tube hydrophone to be tested. The end of the circular tube hydrophone to be tested is located in the countersunk hole and has an interference fit with the top cover. A lead hole is also opened on the top of the top cover at the upper end. The lead of the circular tube hydrophone to be tested passes through the lead hole and is connected to the input end of the preamplifier. The preamplifier is packaged in a metal shell on the outside and contains a preamplifier circuit inside. The preamplifier is placed above the hydrophone to be tested and fixed inside the circular tube formed by the semicircular tube and the Hafu tube, and the wires leading out from the output end of the preamplifier are clamped by the end cap. The exciter is installed on the corresponding chassis mounting hole; The accelerometer is connected to the vibrator to ensure that the circular tube hydrophone to be tested and the accelerometer maintain the same amplitude during vibration; The base and the Hafu are both made of metal.

2. The device for measuring the axial acceleration sensitivity of a circular tube hydrophone according to claim 1, characterized in that: The semicircular tube and the Hafu are enclosed into a circular tube and then fastened with screws.

3. The device for measuring the axial acceleration sensitivity of a circular tube hydrophone according to claim 2, characterized in that: A protrusion with an inner diameter of 11.8 mm and an angle of 120° extends from the middle of the inner wall of the semicircular tube.

4. The device for measuring the axial acceleration sensitivity of a circular tube hydrophone according to claim 1, characterized in that: Select the installation position according to the length of the cylindrical hydrophone to be tested, use long screws to pass through the corresponding screw holes on the side wall of the Hafu to tighten the top cover, so that the gap between the Hafu as a whole and the cylindrical hydrophone to be tested is set, and the other screw holes without long screws are closed with screws.

5. The device for measuring the axial acceleration sensitivity of a circular tube hydrophone according to claim 1, characterized in that: The base, Hafu, end caps and top cover are made of aluminum alloy.

6. The device for measuring the axial acceleration sensitivity of a circular tube hydrophone according to claim 1, characterized in that: The operating frequency band of the preamplifier circuit is 10Hz~10kHz, and the output is in differential form with an amplification of 40dB.

7. The device for measuring the axial acceleration sensitivity of a circular tube hydrophone according to claim 1, characterized in that: The sensitivity of the accelerometer 7 is 100 mv / g.

8. The device for measuring the axial acceleration sensitivity of a circular tube hydrophone according to claim 7, characterized in that: When the accelerometer is in use, one side is connected to the accelerometer power supply and the analog signal is connected to the oscilloscope.

9. The measuring method of the circular tube hydrophone axial acceleration sensitivity measuring device according to any one of claims 1 to 8, characterized in that: The accelerometer and chassis of the measuring device are fixed on the table of the rigid vibration table, and the axial vibration acceleration of the circular tube hydrophone to be tested is measured by the accelerometer; the circular tube hydrophone to be tested and the accelerometer are powered by the low-voltage power supply and the accelerometer power supply respectively, the vibration table keeps vibrating in the vertical direction, and a sinusoidal signal of a specific frequency is sent out by the signal source and amplified by the power amplifier and transmitted to the vibration table; then the circular tube hydrophone to be tested converts the acquired sound pressure information into an electrical signal, and inputs it into the preamplifier and the filter for further processing, and the peak-to-peak value U of the processed voltage of the circular tube hydrophone to be tested and the accelerometer is converted into an electrical signal. H with U a The open-circuit voltage at the output end is displayed on the oscilloscope. Finally, according to formula (1), the axial acceleration sensitivity M of the circular tube hydrophone to be tested can be obtained: a : Where M ar is the sensitivity of a standard accelerometer.

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